Electron velocity sorting discharge device



Feb. 10, 1948.

P. L. HARTMAN ELECTRON VELOCITY SORTING DISCHARGE DEVICE' Original Filed Dec. 20, 1941 2 Sheets-Sheet 1 IN Vb N TOR By P. L.HAR TM4N AT TORNE I" Feb. 10, 1948.

P. L. HARTMAN ELECTRON VELOCITY SORTING DISCHARGE DEVICE 2 Sheets-Sheet 2 Original Filed Dec. 20, 1941 FIG. 4

OUTPUT FIG. 5

lNl ENTOR P. l. HARTMAN flaw/ 4 7% ATTORNEY Patented Feb. 10, i948 V 2,435,586 1 ELECTRONVELOCITYSORTING.DISCHARGE nsvrcn Paul L. Hartman, New York N. Y.,.asslgnor to Bell Telephone Laboratories, Incorporated, New

York, N. Y.,a.corporation"of New-York Original-application December 20, IMlJSeriaINo.

423,788. Divided and this application December 30, 1943. Serial No. 516,290

This invention relates to :systems employing electron discharge devices andparticularly to the design and operation of*suchsystems-for use :at ultra-high frequencies.

An objectof the invention is to extend to .still higher frequenciestthe usefulness :of electron discharge devices'designed for'highfrequency operation by using speciallyadapted lelectrodes, connecting circuits and "modes Ofcperation.

A featurei'ofthe invention is the use of coaxial electrodes and transmission lines :for input and output oonnec-tions'of the-electron discharge device in anu-mber of arrangements particularly adapted for operationina wide rangeof frequencies including the centimeter: wave length range.

Another .feature is the use otareflecting or retarding potential to effect a process of velocity sorting of the electrons :in a 'veloci tyyaried electron stream.

This application is a division of mycopending application, serial ,No.423,788,'iiled December .20, .1941. V Y

Other objectsfiand reaturesare brought out in the following description with reference to the accompanying drawings, whilethe scope of the invention .isdefined in the appended claims.

Inv the drawings: V

Fig. 1 is a perspective view, partly-broken away, of an embodiment of theinvention Fig. 2 is a cross-sectional vview oi a portion'oi the structure of Fig. 1; v

Fig. 3 is a schematic diagram of circuit connections for the arrangement-of'Figs. l and :2;

Fig. 4 is a perspective view; partlyrbroken away, of another embodiment otthe invention; and

Fig. 5 is a cross-sectional view of aportion-of the structure of Fig.4.

.Fig. l-shows an arrangement operating on the principle -of electron velocity sorting .or filtering, and suitablev tor insertion betweentuned coaxial transmission lines; :An input section of. line with an inner conductor -80 and an outer conductor al is shown entering an insulating evacuated envelope 8'2 through-suitable seals. The inner conductor this preferably hollow; at least at the end within the-envelope and mergesinto a fluted cathode 84 shown more clearly by -cross-sectlon in Fig. '2. A section ofthe" outer conductor Bl within the envelope and opposite. cathode 84 is provided witha plurality-of axial slots .85, one opposite the center K of each concave portion of the cathode. An insulated .heatingelement 86 is supportedin an axial position within the-cathode 84 vin-any suitable and theencls of the 2 Claims. (on. 31539-) element at are brought out through the conductor-s 80, 8| and through thewenvelope 82 in any suitable manner, not'shown, the connections to the elementsfi beinginsulated from the conductors'8lL-8'l.

Opposite each of the :slots 85 is suitably mounteda pair oficurved substantially parallel plates 81', its whichmayibe of-circular cylindrical shape andipreferably have a :mean circular arc of approximately 127 degrees.

The assembly of plates 81, 88 is enclosed in a hollow conductive corrugated tube Bil as shown, the outer opening betweeneach individual pair of plates '81, 88 bei11g close to :one of the normgations in the tube "89.

" At the end of the envelope 82 oppositethe input transmission line 80, '8! there is sealed an output coaxial transmission line with inner condoctor 99 and outer conductor 9|. The inner conductor Qllzterminates inside the envelope 92 whereitis conductively connected-to the assembly comprising the plurality of plates 81, 88 through biasing means as hereinafter more fully described. The outer conductor 91 flares to merge with the tube 89 but iswinsulated there- I fromby a suitable coupling section 91..

In the-operation of the system of Figs. v1 and 2 the element lit, when heated, serves to heat the cathode 84 .and'by'virtue of the-shape of the fluted surface of the cathode 84 a sheet of electrons is omitted and focused to pass through the slotrfiii, there being a sheet .of electrons for each slot 85.

The operation of the various elements of the tube will be more readily understood from Fig. 3 which is aschematic diagram including the connecting circuits. The anode element 89 is paced at a relatively high positive potential with respect to the cathode 84 by means of the combined voltage of batteries 92, 93 and 96 preferably through an inductive element I94, which latter, at ultra-high frequencies, may comprise merely :thev inductance of a short length of conductor. The platesz8l, 88 are'biased to slightly different potentials with respect to the junction point between the batteries 92 and 93 by means of batteries 534 and 95. respectively, or by other suitablemeans. Thepotential difference between the cathode B4 and a grid is adjusted to a small positive or negative value by means of a potentiometer across the battery 96. It willbe understood that any'or all of the batteries shown may be replaced by any other suitable sources of direct'electromotiveforce. Electrodes 85, 81 and .83 are preierably connected together for high frequencies by means of built-in by-pass condensers.

A high frequency wave to be amplified may be impressed upon the input transmision line 80, 8| by a suitable source 98 and the output transmission line may be connected with a load represented by a resistor 99. The input line and the associated cathode and heater leads are represented in Fig. 3 by an equivalent transformer I30 tuned by a condenser I 3I. The source 98 will set up a pulsating potential difference between the cathode 84 and the grid 85' thereby impressing a succession of velocity variations upon the electrons in the stream emerging from the cathode. Depending upon the fixed potential difference between the plates 81 and. 88 the electrons will follow various curved paths in the space between the plates under the influence of the transverse electric field therebetween. Within a certain narrow range of velocities all the electrons entering the space between the plates with such velocities will emerge at the far end without striking either of the plates and be drawn to the anode 89. Electrons having velocities below the critical range will strike the plate 81 and electrons having velocities greater will strike the plate 88. Hence, if the system is adjusted so that the'potential difierences impressed by the input waves are such as to vary the electron velocities through the critical range, the electron current to the anode 89 will be varied, thereby generating a high frequency current in the output circuit. It will be evident that the high frequency component of the output current will be transmitted to the load 99 through the output transmission line 90, 9 I.

The system may be adjusted for operation either as an amplifier, an oscillator, a detector, or a; frequency doubler. By adjusting the po tentials of the several electrodes either so that substantially no electrons or substantially all the electrons reach the anode 89 in the absence of any high frequency excitation the system acts as a detector, responding to changes in the amplitude of an impressed high frequency wave. When using the system asa detector the output circuit may be tuned to the input frequency to take advantage of regenerative amplification and the detected output may be received in any suitable device incorporated in the load 99.

' Amplification is secured when the potentials of the several electrodes are adjusted to reduce the current, preferably to half of its maximum value, in the absence of excitation. With an am plifying adjustment, the impressed high frequency wave will cause fluctuations above and below the initial anode current value to produce a replica of the impressed wave in the anode circuit.

' It will be evident also that the system may be adjusted to give either one or two output pulses for each cycle of the input wave, thereby giving either amplification or frequency doubling, the latter adjustment being similar to the adjustment for a detector.

An alternative arrangement operating on the same principle as the system of Figs. 1, 2 and 3 is shown in Figs. 4 and 5. The arrangement of the elements is seen most readily by cross-section in Fig. 5. The cathode IOI has but two active surfaces both of which are fluted as are the surfaces of the cathode 84 in Fig. 2. A pair of focusing electrodes I02 and I03 are provided between the cathode IOI and enlargements I04 and I05 respectively, of a pair of concentric cylinders I06 and I01. The non-enlarged portions of the cylinders I06, I01 form a pair of arcuate velocity filtering elements, one on either side of the cathode I 0I. The are subtended by each filtering element is again'preferably approximately I21 degrees. A common anode I08 is provided enclosed by enlargements I09 and H0 respectively, of the cylinders I06 and I01. A heating element III is provided within the hollow interior of the cathode IOI, the ends of the element III being suitably brought out through a hollow inner conductor H2 forming part of an input coaxial line, shown at the right of Fig. 4, and having an outer conductor H3. The inner conductor H2 is conductively connected to the cathode IN. The outer conductor H3 flares to merge into the enlargement I04. The anode I08 merges with the inner conductor H4 of an output coaxial line of which the outer conductor H5 is flared to merge with the enlargement I09. Any suitable means may be provided to support the coaxial lines and the various electrodes and the assembly may be suitably enclosed by a vacuum-tight insulating envelope H6, the latter serving incidentally as a support. For example, the outer conductor H3, enlargement I04, cylinder I06, en-

largement I09 and outer conductor II5 may be integral and supported by the envelope surrounding the conductor H5 at the left and the conductor H3 at the right. The cathode IOI. electrodes I02 and I03, and cylinder I01'may be supported by the conductor H2 properly sealed into the envelope, and the leads from the heater I II and from the other electrodes comprising members IOI, I02, I03, I01 may be brought out through the hollow interior of conductor H2. The anode I 08 may be supported by the conductor H4 properly sealed into the envelope. Built-in by-pass condensers are preferably provided connecting elements I02, I03, I05, I00 and I01 together for high frequencies.

In the operation of the system of Figs. 4 and 5, with suitable biasing potentials applied, a sheet of electrons emerges from either side of the oathode IOI, passes through the slots in the focusing electrodes I02 and I03, and enters the space between the cylinders I06 and I01. In the critical range of electron velocities the sheet of electrons reaches the anode I08. At other electron velocities the electrons are intercepted by One or the other of the cylinders I06 and I01, as described in connection with Fig. 3.

What is claimed is:

1. A space discharge device comprising inner and outer hollow coaxial cylindrical conductors insulated from each other, said outer conductor constituting an anode and said inner conductor constituting a grid and having a plurality of axially extending slots therein, a plurality of velocity filters for electrically charged particles, each of said filters comprising a pair of curved spaced substantially parallel conductive plates disposed betweensaid anode and said grid and having two pairs of axially extending ends, each pair providing an opening to the space between said plates: said openings being for input and output of charged particles respectively, the input opening of each filter being aligned with a respective slot in said grid structure and the corresponding output opening being in proximity to said anode, a cathode mounted axially within said grid, means coupled to said anode for supplying a potential with respect to said cathode, and means coupled to said plates for biasing one respective plate of each said filter at one potential with respect to said cathode and the other respective plate in each filter at another slightly different potential with respect'to said cathode, said two potentials being intermediate the potential of the said cathode and' the potential of the said anode. v

2. The combination of'clairn 1 in which the anode is axially corrugated forming a plurality of inner surface portions each portion being substantially perpendicular to the plates of one of said filters opposite the said output opening of the respective filter.

PAUL L. HARTMAN.

6 REFERENCES CITED The following references are of record in th file of this patent:

UNITED STATES PATENTS Number Name Date 2,368,031 Llewellyn Jan. 23, 1945 2,207,846 Wolff July 16, 1940 2,169,396 Samuel Aug. 15, 1939 2,157,585 Zworykin et a1 May 9, 1939 2,173,267 Strutt et a1 Sept. 19, 1939 2,254,793 Burstyn Sept. 2, 1941 2,061,387 Prinz Nov. 17, 1936 Klemperer Dec. 6, 1938 

